Electric motor powered wheeled vehicles are well known in the art and have sparked continued interest as an alternate power source for human transport. One problem in the development of electric vehicles suitable for modern demands is the difficulty of producing a vehicle of reasonable cost, size and performance using available electric power storage systems.
Electric powered vehicles compete with internal combustion powered vehicles as transportation and in view of such must provide a great many of the conveniences of operation found using modern internal combustion vehicles. Thus, it is considered necessary for general acceptance of an electric powered vehicle that it have the ability to operate at reasonable highway speeds, e.g. 50-70 mph, have reasonable operational longevity between down time charging, and must have reasonable power and vehicle response over typical roadway terrain and conditions which might be encountered.
Electric vehicle speeds of 50-70 mph have not been a significant problem to attain, however attaining and maintaining such speeds, while achieving reasonable operational longevity, has been problematic. To solve such problem, electric vehicles have been fitted with diverse electricity generating and storage means. For example, solar generators, wind generators and even small gasoline, natural gas and the like fueled generators have been fitted to electric vehicles to generate electricity as it is being used and replenish and extend the life of battery systems currently used to power electric vehicles. Improved battery systems having deep cycle charges have been developed, but the cost and weight of sufficient numbers of such batteries to extend range have created further problems which negate the acceptance of electric vehicles as a popular transportation choice.
In an effort to extend the operational range of electric powered vehicles, hybrid arrangements of electric motors with alternate fuel engines have been proposed to be added to electric powered vehicles. By the term alternate fuel engine is meant engines which are fueled by gasoline, diesel, natural gas, hydrogen, compressed air, steam and the like such as internal combustion engines, turbines and the like. In such arrangement an electric motor is generally arranged as the primary vehicle drive, powered by a bank of batteries, with the vehicle additionally containing an alternate fuel engine which drives a generator enabled to regenerate electric battery storage during and/or intermittent with power use by the electric motor. An advantage of such hybrid arrangements is that small horsepower alternate fuel engines can be used for electricity replenishment, which can be enabled at constant, energy efficient speeds to use small quantities of fuel to regenerate electricity and thus significantly increase the operational range of the electric powered vehicle. Since most calculations for vehicle fuel efficiency are concerned with fuel burned on board the vehicle, such arrangements are viewed as being very efficient in miles per gallon of fuel consumed.
In some hybrid embodiments, the alternate fuel engine regenerating arrangement can be shifted to directly engage the drive train of the vehicle, typically in emergency situations. Such enablement is usually provided for situations when stored electric power is too low to power the electric motor drive of the vehicle, but since the alternate fuel engine is generally of low horsepower, they are generally inadequate for normal drive use.
In the operation of a wheeled vehicle for general transport, the driving event is one where the vehicle is intermittently powered, braked and otherwise caused to change the speed and force which must be delivered to the drive wheels of the vehicle.
An object of the present invention is to use various changes in the vehicular driving event to replenish and extend storage battery systems powering an electric vehicle.
Another object of the present invention is to provide an improved system for regenerating batteries in an electric motor powered vehicle, using energy means which is otherwise lost during changes in the driving experience.
A still further object of the invention is provide a simple, efficient and inexpensive transmission for varying speed and power from an electric motor drive source to the wheels, which can be conveniently arranged in enabling a iregenerating system for extending the life of a storage battery system.
Yet another object of the invention is to provide a transmission means to enable convenient and efficient hybrid embodiments of an electric motor drive vehicle.
These and other objects will become apparent from the following recitation of the invention.
In its simplest mode, the present invention combines a simple, efficient and inexpensive transmission suitable for varying the speed and power delivered to drive wheels of a vehicle, with a power regeneration loop arranged to utilize energy otherwise wasted during the driving experience.
In a preferred arrangement of the invention, a high output transmission comprising a planetary drive with means connected to an electric motor, is arranged as a variable speed translator within a vehicle drive train, with vehicle power and speed being enabled by automatically increasing and decreasing gear ratios in cooperation with variations in electric motor speed and output power needs.
The high output transmission of the invention comprises a planetary drive means which utilizes an incrementally scheduled means to resist the rotation of an idler wheel member for automatically transferring power in infinite increments through a defined range of gear ratios to and from opposing output and input drive means of the planetary.
In one arrangement of the invention, an electric motor, powered by a battery storage system, drives a planetary input member which in turn has an output member arranged to drive a vehicle wheel. The electric motor driven input member is in planetary arrangement with an output member and an idler member, with variable resistance of rotation being imposed upon the idler member to define the rotation and geared ratio of the output member in respect to the driven input member. The arrangement includes a generator in an arrangement which imposes incremental scheduled resistance of rotation upon the idler member, with the resistance of rotation being sufficient to enable translation of electric motor rotation to the output drive and accordingly the vehicle wheel(s). The generator arrangement is such as to produce regenerative electricity for input to the battery storage system as a functional consequence of resistance of rotation of the idler member, and stops producing regenerative electricity when rotation of the idler member is stopped.
In a typical sequence of driving events to initiate movement of a vehicle in such arrangement, the electric motor provides a selected rotational speed to the input member which rotates an idler member. The idler member is incrementally restricted by the generator arrangement to automatically provide incrementally increasing output to the wheels, infinitely through a defined range of gear ratios, up to a scheduled intermediate state gear ratio or to the highest transmission gear ratio of the transmission. The generator is arranged to produce power in accord with the rotation of the idler member, intermittently or continuously generating electricity for replenishing a battery storage system.
In such arrangement of the invention, the vehicle maintains speed as determined by the selected speed of the electric motor and the transmission gear ratio automatically selected through the planetary arrangement in accord with the resistance of the vehicle to motion. Thus, at any selected motor speed wherein resistance to movement of the vehicle is such that the planetary transmission gear ratio is less than at its highest ratio, the idler member rotates and enables generation of electricity for replenishment of the battery storage system.
For example, when a vehicle is traveling in a generally level plane, with the electric motor at a selected speed and the transmission operating at an input:output gear ratio other than the highest ratio attainable, the idler is rotating and the generator is enabled for generation of power to the battery storage system. When vehicle inertia tends to increase the vehicle speed, as for example going downhill, with no change in selected speed of the electric motor, the transmission automatically incrementally moves downward to a lower gear ratio which increases the rotation of the idler member and concurrently changes the rate and amount of generation of electricity by the generator, continuing through the end of that inertial experience of the vehicle.
If the driver increases vehicle speed by increasing the selected speed of the electric motor, the transmission automatically incrementally moves from a higher to a lower gear ratio with concurrent idler member rotational increase and changed generation of electricity until a steady maintained speed is reached as defined by the new selected motor speed at either the maximum gear ratio attainable or at a steady state intermediate ratio. If the vehicle is caused to decrease speed, by the driver decreasing the selected speed of the electric motor, the transmission automatically incrementally moves downward through its defined gear ratio changing generation of electricity by increasing idler member rotation, continuing until the vehicle is stopped with power to the electric motor disengaged. Thus, electrical regeneration occurs intermittently and/or continuously, throughout the driving experience, at rates commensurate with intermittent and incremental changes in vehicle speed.
Such arrangement is particularly suitable for use in hybrid embodiments. In one hybrid embodiment, a vehicle is enabled for electric motor drive of one axle and/or wheel with another axle and/or wheel being enabled for drive by an alternate fuel engine. Thus, for example an electric motor having a through-put shaft extending from both ends thereof, or two independent electric motors, is mounted between two front or rear wheels of a vehicle, each shaft end being connected to the input of a planetary transmission of the invention and each output of the respective transmissions being connected to drive a wheel. The idler members of both transmissions are arranged to drive a generator. When the electric motor is engaged to drive the vehicle, the input shafts of both planetary transmissions are rotated and both wheels of the vehicle are driven with regeneration as before described. Since planetary arrangements are on both sides of the electric motor it can be used on a rear or front axle, with differences in front wheel speed occasioned by parallel steering radii being automatically compensated through the variable ratio of the independently functioning planetary transmissions.
When the electric motor is not engaged, as for example a wheel and/or wheels of another axle being driven by the alternate fuel engine, the electric motor is braked from turning but the wheels are still engaged with the moving vehicle and turning idler members are regenerating the bank of storage batteries. When both the alternate fuel engine and the electric motor are engaged, the vehicle functions as a true 4 wheel drive vehicle. This embodiment has particular military interest in that it can provide a vehicle with an easily engaged or disengaged stealth capability, alternate independent emergency power supply enablement through an alternate fuel engine, hybrid battery regeneration and convenient 4 wheel and/or alternate axle 2 wheel drive selection.
In another hybrid embodiment, the planetary transmission of the invention is arranged between an alternate fuel engine and an electric motor along a drive train of the vehicle. In such arrangement, an electric motor having a through-put shaft extending from both ends has one shaft end connecting to the vehicle wheel drive, and the other shaft end connecting to a first input/output shaft of a planetary transmission of the invention. A second input/output shaft of the transmission is connected to the driven output shaft of an alternate fuel engine, the idler member is in enabling arrangement with a generator, and the alternate fuel engine may be in further enabling arrangement with another generator.
In such hybrid arrangement, the alternate fuel engine driven output shaft, input/output shafts of the transmission and electric motor shaft, are preferably arranged with rotating shafts along about a common axis and enabled for independent and/or cooperative engagement of both the electric motor and alternate fuel engine in the tasks of driving the vehicle wheels and/or regeneration of battery storage banks. Thus, in one preferred embodiment, the electric motor provides the primary vehicle driving force, with an alternate fuel engine operating at an efficient constant idle speed to regenerate stored electricity and/or directly supply power to the electric motor on an as needed basis.
With the electric motor under power, both ends of the motor shaft provide power output, one end to the wheels of the vehicle, the other end to a first input/output shaft of the planetary transmission. Whether or not the rotation of the electric motor shaft is from electric powered enablement or inertial movement of the vehicle wheels, the connection to the planetary transmission enables the idler member to rotate and generate electricity. Restraining the idler member from rotation enables the rotation of the second input/output shaft of the planetary to the engine.
The driven shaft of the internal combustion engine is arranged to provide output to a second input/output shaft of the planetary. Input of power from the internal combustion engine to the second input/output shaft also enables the idler member to rotate and generate electricity, and when the idler member is restrained, enables the rotation of the first input/output shaft of the planetary transmission.
Such hybrid arrangement provides a multiplicity of different adaptations within a hybrid powered vehicle for both efficiency and fuel preservation. For example, in one adaptation hard connections may be used among the shafts of the alternate fuel engine, planetary transmission and electric motor, such that with appropriate selection of transmission ratios and coordinated restraint of the idler member, the drive shaft of alternate fuel engine may be enabled to rotate at a constant speed powering a generator independent from the planetary transmission and be engaged and disengaged to assist the rotation of the electric motor by varying the restraint upon the idler member. In another example, an alternate fuel engine can be increased in speed from a normally constant speed, through a kick-down enablement position of an accelerator pedal, which is coordinated with restraint on the idler member.
In another adaptation, clutch means may be provided for controlled engagement among the shafts of the alternate fuel engine and the planetary transmission and/or the electric motor and the planetary transmission. For example, clutch means interposed among the drive shaft of the alternate fuel engine and the planetary transmission enables operational interruption of the alternate fuel engine from the electric motor/planetary transmission/vehicle drive system; while clutch means interposed among the planetary transmission and the electric motor enables operational interruption of the electric motor/vehicle drive system from the planetary transmission/alternate fuel engine system. Positioning of the clutch means between the alternate fuel engine and the planetary transmission is generally preferred to enable different gear ratios than possible through the planetary transmission and/or to provide improved operation of the vehicle when powered solely by the alternate fuel engine.
Positioning the clutch means between the planetary transmission and the electric motor is generally preferred when the vehicle is to be primarily electric motor driven, with regeneration dependent primarily upon the alternate fuel engine. In such mode, secondary regeneration is generally also connected downstream from the transmission toward the driven wheel for operation with any transmission and/or a further planetary transmission.
Multiple additional hybrid adaptations of the invention are apparent, such as for example the use of an AC electric motor, with or without a significant invertible storage battery presence, wherein the alternate fuel engine directly generates AC current for use by the electric motor and interacts with the planetary transmission of the invention to generate DC current for a storage battery utility and/or to assist the AC motor during the driving experience to provide improved vehicle driving performance. Such arrangement enables use of AC motors which are resistant to starting under load. For example AC motors have significant power-draw at start-up and three phase motors are generally not considered practical for vehicle embodiments because of initial start-up concerns. In a hybrid embodiment as contemplated in the present invention, wherein the alternate fuel engine is enabled to assist start up of an electric motor, power-draw by the AC motor is significantly reduced and three phase motors become practical for use. Indeed, such arrangement even contemplates the combination of low horsepower alternate fuel engines driving an AC generator, specifically including three phase AC generating means, which is arranged to directly power an AC operating motor specifically including a three phase motor. Such direct power arrangement obviates the use of large banks of storage batteries and enables the use of a small battery storage bank which enable other vehicle needs and/or can be tapped for reserve storage on an intermittent as needed basis and/or which are recharged through operation of the on-board generating means.
It is believed that under typical driving conditions wherein the vehicle is caused to intermittently stop, start, slow down and increase speed in accord with terrain and/or traffic conditions, that the regenerative storage battery arrangement of the invention without hybrid enablement can increase range of an electric vehicle from about 20 to greater than about 70 percent as compared to non-regenerative systems, and that embodiments with hybrid enablement can provide generally unlimited range and even improved vehicle driving performance.